Pretreatment method for enhancing peroxide to improve leaching rate of high-sulfur-arsenic gold ore

Abstract

The invention belongs to the technical field of hydrometallurgy, and particularly relates to a pretreatment method for enhancing peroxide to improve the leaching rate of high-sulfur-arsenic gold ore. Comprising the following steps that the high-sulfur-arsenic gold ore is ground and then prepared into ore pulp; an oxidizing agent is added into the ore pulp, oxidation pretreatment is conducted on the high-sulfur-arsenic gold ore under the catalytic action of ultraviolet light, and ore pulp activation liquid is formed; and the pH of the ore pulp activating solution is adjusted to 9-12, a gold leaching agent is added into the ore pulp complexing solution, and stirring gold leaching treatment is conducted. According to the method, efficient oxidation of sulfide and arsenide is achieved under the mild condition through the synergistic effect of photocatalysis and chemical oxidation, the leaching rate of gold is remarkably increased, compared with a conventional peroxide oxidation method for pretreatment, the leaching rate can be increased by 10%-35%, and meanwhile the agent use amount and environmental pollution are reduced.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically relating to a pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides. Background Technology

[0002] High-sulfur arsenic gold ore is a complex gold ore that is difficult to process, as the sulfides and arsenides in it severely affect the gold leaching efficiency. Currently, traditional methods for processing high-sulfur arsenic gold ore mainly include roasting, pressure oxidation, and biological oxidation, but these methods all have significant drawbacks.

[0003] Calcination is one of the earliest processing methods, which oxidizes and decomposes sulfides and arsenides at high temperatures, such as 500℃~700℃. However, this method produces a large amount of sulfur-containing oxides, SO₂. x It produces toxic gases such as arsenic trioxide (As₂O₃), causing serious environmental pollution. Furthermore, the roasting process is energy-intensive, requires significant equipment investment, and incurs high processing costs. While the roasting method for high-sulfur arsenic gold ore achieves a gold leaching rate of over 85%, the energy consumption per ton of ore roasted is approximately 1200 kWh, and it necessitates a complex tail gas treatment system, resulting in high operating costs.

[0004] Pressure oxidation typically involves oxidizing sulfides and arsenides using pressurized oxygen under high temperatures of 180℃ to 225℃ and high pressures of 1.5MPa to 3.5MPa. While this method can achieve high gold leaching rates (over 90%), it also results in severe equipment corrosion, high safety risks, and high investment and operating costs. For example, the pressure oxidation process used by a foreign company requires equipment investment approximately 3 to 5 times that of conventional cyanidation processes, and also involves significant material and energy consumption.

[0005] Biological oxidation utilizes microorganisms such as Thiobacillus acidophilus to oxidize and decompose sulfides and arsenides, offering the advantage of low environmental pollution. However, the oxidation cycle is long, typically requiring 5 to 15 days, and is greatly affected by environmental factors such as temperature and pH, resulting in unstable oxidation efficiency. While biological oxidation avoids gas pollution from roasting, its processing cycle exceeds 10 days, and its oxidation efficiency is significantly affected by seasonal variations, limiting its industrial application.

[0006] In recent years, researchers both domestically and internationally have attempted to treat high-sulfur arsenic gold ores using chemical oxidation methods, such as directly oxidizing the minerals with strong peroxides like hydrogen peroxide and sodium hypochlorite. While these methods can be carried out at room temperature and pressure, their oxidation efficiency is low, peroxide consumption is high, and economic viability is poor. For example, using a 3% hydrogen peroxide solution to oxidize high-sulfur arsenic gold ores only increases the gold leaching rate by 10 to 15 percentage points, and the high peroxide consumption leads to high costs and potential environmental pollution. Summary of the Invention

[0007] The purpose of this invention is to provide a pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides. This method aims to solve the problems of low leaching rate, high cost, and serious environmental pollution in the treatment of high-sulfur arsenic gold ore in the prior art. By utilizing the synergistic effect of photocatalysis and chemical oxidation, the method achieves efficient oxidation of sulfides and arsenides under mild conditions, thereby significantly improving the gold leaching rate.

[0008] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0009] The purpose of this invention is to provide a pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides, comprising the following steps: S1. Grind the high-sulfur arsenic gold ore and prepare it into a slurry.

[0010] It should be noted that the present invention grinds and prepares a slurry from high-sulfur arsenic gold ore. The solvent used to prepare the slurry is water, in order to ensure optimal reaction kinetic conditions.

[0011] S2. Add an oxidant to the slurry and perform oxidation pretreatment on the high-sulfur arsenic gold ore under ultraviolet photocatalysis to form a slurry activation solution.

[0012] It should be noted that this invention uses ultraviolet light and oxidants to form a synergistic system of photocatalysis and chemical oxidation. Ultraviolet light can excite the oxidant, causing it to decompose and generate highly active free radicals, mainly including hydroxyl radicals (·OH) and sulfate radicals (SO4·). These free radicals have extremely strong oxidizing properties, and their redox potentials are much higher than those of conventional oxidants, enabling them to efficiently oxidize sulfide and arsenide minerals.

[0013] During mineral oxidation, the highly reactive free radicals generated react with sulfide and arsenide minerals. The main reaction mechanisms are as follows: FeS2+8·OH→Fe 2+ +2SO4 2- +4H₂O + 2e - .

[0014] FeAsS + 14·OH → Fe 3+ +AsO4 3- +SO4 2- +H₂O + 2e - .

[0015] FeS2 + 16SO4· + 8H2O → Fe 2+ +18SO4 2- +16H + .

[0016] FeAsS + 14SO4· + 8H2O → Fe3+ +AsO4 3- +15SO4 2- +16H + .

[0017] Photocatalysis not only generates highly reactive free radicals but also promotes the decomposition of peroxidants, thereby improving oxidation efficiency. The main reason why peroxides such as persulfate and hydrogen peroxide exhibit enhanced oxidizing power under high-pressure mercury lamp irradiation is the generation of stronger oxidizing free radicals through photolysis.

[0018] Among them, persulfate S2O8 2- Under ultraviolet light irradiation from a high-pressure mercury lamp, a homolytic cleavage reaction occurs, generating sulfate radicals (SO4). - • The reaction mechanism is similar to S2O8 2- In +hν →SO4 - These sulfate radicals possess extremely strong oxidizing properties, with a standard redox potential of approximately 2.6V, far exceeding that of persulfate itself. Hydrogen peroxide (H₂O₂) decomposes under ultraviolet light to generate hydroxyl radicals (·OH), as in the reaction H₂O₂hν→2•OH. The standard redox potential of hydroxyl radicals is as high as 2.8V, making them one of the strongest oxidizing agents, far stronger than hydrogen peroxide itself. Furthermore, the generated radicals enhance the oxidizing power through further reactions, including reactions with water molecules: SO₄²⁻ - +H2O→SO4 2- +·OH+H + Hydroxyl radicals can also undergo hydrogen atom abstraction reactions with organic matter: ·OH + RH → H₂O + R·; sulfate radicals can directly oxidize organic matter: SO₄²⁻ - +RH →SO4 2- +H + +R·.

[0019] The photocatalytic oxidation process not only disrupts the crystal structure of sulfide and arsenide minerals but also activates the mineral surface, increasing surface defects and active sites, which is beneficial for the dissolution of gold during subsequent cyanide leaching. Simultaneously, the oxidation process removes the sulfide and arsenide films coating the surface of gold particles, allowing the gold particles to be fully exposed to the leaching agent.

[0020] Based on this, the present invention achieves highly efficient oxidation of sulfides and arsenides through a synergistic mechanism of photocatalysis and chemical oxidation, significantly improving the gold leaching rate while reducing environmental pollution.

[0021] S3. Adjust the pH of the slurry activation solution to 9-12, add gold leaching agent to the slurry complex solution, and perform stirring and gold leaching treatment.

[0022] It should be noted that this invention utilizes a gold leaching agent. Furthermore, under the pretreatment method of this invention, the ultraviolet photocatalysis and oxidation process effectively exposes the gold particles, allowing the gold leaching agent to react more directly with the gold. This results in the formation of a stable complex between the gold leaching agent and the gold in the slurry, achieving highly efficient leaching.

[0023] In some specific embodiments, ultraviolet photocatalysis is performed using a high-pressure mercury lamp with a power of 100W to 30000W.

[0024] It should be noted that the present invention uses ultraviolet light emitted by a high-pressure mercury lamp to irradiate the slurry system, which can excite oxidant molecules and cause them to decompose to produce highly active free radicals. Multiple high-pressure mercury lamps can be used, and the irradiation can be performed on the outside or inside of the slurry. When irradiating inside the slurry, the high-pressure mercury lamps need to be waterproofed.

[0025] In some specific embodiments, the concentration of the oxidant in the slurry is 0.0001 mol / L to 3 mol / L.

[0026] In some specific embodiments, the oxidant is at least one of a peroxide or a persulfate.

[0027] It should be noted that the persulfates used in this invention are potassium persulfate, ammonium persulfate, sodium persulfate, etc., which have strong oxidizing properties. The free radical oxidation mechanism of persulfates such as potassium persulfate is: S2O8 2- +hv→2SO4·. The peroxides used in this invention are hydrogen peroxide, sodium peroxide, potassium peroxide, persulfides, etc., which have strong oxidizing properties. The peroxide generates free radicals through the oxidation mechanism: H2O2 + hv → 2·OH. Highly active free radicals are generated through the decomposition of the oxidant, which achieves efficient oxidation of sulfides and arsenides under mild conditions, significantly improving the gold leaching rate.

[0028] In some specific embodiments, the oxidation pretreatment temperature is 10℃~90℃, the time is 12h~24h, and the stirring rate is 80r / min~500r / min.

[0029] It should be noted that the present invention achieves efficient oxidation of sulfides and arsenides under mild conditions, without the need for high-temperature roasting or high-pressure equipment, thus significantly reducing energy consumption; at the same time, by controlling the oxidation conditions, the emission of harmful gases is reduced.

[0030] In some specific embodiments, the concentration of the gold leaching agent in the slurry activation solution is 0.01 mol / L to 1 mol / L.

[0031] In some specific embodiments, the gold leaching agent is at least one of the following: copper amine system sodium thiosulfate, cyanide-containing leaching agent, thiourea, chloride, cicada, or green gold.

[0032] It should be noted that the gold leaching agent involved in this invention includes, but is not limited to, sodium thiosulfate in the copper amine system, cyanide-containing leaching agent, or at least one of Jinchan, Shengde, and Green Gold, as long as it forms a stable complex with the gold in the slurry to achieve efficient leaching. The most suitable leaching agent can be selected according to actual needs.

[0033] When the gold leaching agent is a cyanide-containing leaching agent, such as NaCN or KCN, a soluble gold cyanide complex is formed in the presence of oxygen. The reaction equation is: 4Au + 8CN - +O2 + 2H2O → 4[Au(CN)2] - +4OH - This process is specifically an electrochemical process that relies on the oxidation of oxygen. Oxygen acts as a reducing agent at the cathode, while gold dissolves at the anode.

[0034] When the gold leaching agent is thiourea, under acidic conditions, the reaction equation for the formation of a stable complex between thiourea and gold is: Au + 2CS(NH2)2 → Au[CS(NH2)2]2 + +e - .

[0035] When the gold leaching agent is sodium thiosulfate in a copper-amine system, gold forms a stable complex with the thiosulfate. The reaction equation is: 4Au + 8S₂O₃ 2- +O2 + 2H2O → 4[Au(S2O3)2] 3- +4OH - .

[0036] In some specific embodiments, the immersion gold treatment is carried out in an air atmosphere, the immersion temperature is 10℃~90℃, the immersion time is 4h~24h, and the stirring rate is 80r / min~500r / min.

[0037] It should be noted that the pretreatment method provided by this invention is carried out under relatively mild conditions, achieving efficient leaching without the need for high temperature, high pressure or strong acid environment. Leaching under these conditions not only saves energy but also reduces equipment corrosion and wear, extends equipment service life, reduces maintenance and replacement costs, and improves process stability and operability.

[0038] In some specific embodiments, the particle size of the ground high-sulfur arsenic gold ore is more than 90% between 18 μm and 74 μm, and the mass concentration of the slurry is 10% to 40%. It should be noted that, as a preferred embodiment of the present invention, the mass concentration of the slurry is 10% to 40% to ensure optimal reaction kinetics conditions, which has specific technical advantages. When the slurry concentration is too low, such as <10%, the reaction system is too diluted, reducing oxidation efficiency and increasing water consumption and subsequent processing volume; while when the slurry concentration is too high, such as >40%, the solution viscosity is too high, affecting the stirring effect and mass transfer efficiency, leading to uneven reaction and increased energy consumption. The range set by the present invention ensures sufficient reactivity while also considering process economy.

[0039] Compared with the prior art, the present invention has the following advantages: (6) This invention provides a pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides. This invention employs a photocatalytic and chemical oxidation synergistic system formed by ultraviolet light and an oxidant. Ultraviolet light can excite the oxidant, causing it to decompose and generate highly active free radicals, mainly including hydroxyl radicals (·OH) and sulfate radicals (SO4·). These free radicals have extremely strong oxidizing properties, and their redox potentials are much higher than those of conventional oxidants, enabling them to efficiently oxidize sulfide and arsenide minerals. Furthermore, the photocatalytic oxidation process not only destroys the crystal structure of sulfide and arsenide minerals but also activates the mineral surface, increasing surface defects and active sites, which is beneficial for the dissolution of gold during subsequent cyanide leaching. Simultaneously, the oxidation process can remove the sulfide and arsenide films coating the surface of gold particles, allowing the gold particles to be fully exposed to the leaching agent. Based on this, this invention achieves efficient oxidation of sulfides and arsenides through the synergistic mechanism of photocatalysis and chemical oxidation, significantly improving the gold leaching rate while reducing environmental pollution.

[0040] (7) The pretreatment method provided by the present invention is carried out under relatively mild conditions to achieve efficient leaching. It does not require high temperature, high pressure or strong acid environment. Leaching under such conditions not only saves energy consumption, but also reduces equipment corrosion and wear, extends equipment service life, reduces maintenance and replacement costs, and improves process stability and operability. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] It should be noted that the technical terminology used in this invention is for the purpose of describing specific embodiments only and is not intended to limit the scope of protection of this invention. Certain terms are used in this invention to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This invention does not distinguish components based on differences in terminology, but rather on differences in their functions.

[0043] The following specific examples will provide further explanation.

[0044] Example 1 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1 is a typical high-sulfur arsenic gold ore of the Carlin type, with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is 18 μm to 74 μm, accounting for 95%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0045] S2. Add hydrogen peroxide to the slurry at a concentration of 0.15 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for 24 hours to perform oxidation pretreatment and form a slurry activation solution.

[0046] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then cicadas were added at a rate of 20 kg / t. The process was carried out in air atmosphere, and the gold leaching treatment was carried out at 25°C and 500 r / min for 24 h with stirring.

[0047] Example 2 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1 is a typical high-sulfur arsenic gold ore of the Carlin type, with a gold grade of 6 g / t, a sulfur content of 13%, and an arsenic content of 15%. The high-sulfur arsenic gold ore is ground until the particle size is 18 μm to 74 μm, accounting for 95%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0048] S2. Add hydrogen peroxide to the slurry at a concentration of 0.15 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for 24 hours to perform oxidation pretreatment and form a slurry activation solution.

[0049] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then cicadas were added at a rate of 20 kg / t. The process was carried out in air atmosphere, and the gold leaching treatment was carried out at 25°C and 500 r / min for 24 h with stirring.

[0050] Example 3 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1 is a typical high-sulfur arsenic gold ore of the Carlin type, with a gold grade of 18 g / t, a sulfur content of 20%, and an arsenic content of 22%. The high-sulfur arsenic gold ore is ground until the particle size is 18 μm to 74 μm, accounting for 95%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0051] S2. Add hydrogen peroxide to the slurry at a concentration of 0.15 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for 24 hours to perform oxidation pretreatment and form a slurry activation solution.

[0052] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then cicadas were added at a rate of 20 kg / t. The process was carried out in air atmosphere, and the gold leaching treatment was carried out at 25°C and 500 r / min for 24 h with stirring.

[0053] Example 4 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is between 18 μm and 74 μm, accounting for more than 90%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0054] S2. Add hydrogen peroxide to the slurry at a concentration of 0.1 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for oxidation pretreatment for 24 h to form a slurry activation solution.

[0055] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then sodium thiosulfate of the copper amine gold leaching agent system with a concentration of 0.08 mol / L was added. The process was carried out in air atmosphere and gold leaching was performed at 25°C and 500 r / min for 24 h with stirring.

[0056] Example 5 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is between 18 μm and 74 μm, accounting for more than 90%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0057] S2. Add hydrogen peroxide to the slurry at a concentration of 1.0 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for 24 hours to form an activating solution for the slurry.

[0058] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then sodium thiosulfate of the copper amine gold leaching agent system with a concentration of 0.08 mol / L was added. The process was carried out in air atmosphere and gold leaching was performed at 25°C and 500 r / min for 24 h with stirring.

[0059] Example 6 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is between 18 μm and 74 μm, accounting for more than 90%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0060] S2. Add hydrogen peroxide to the slurry at a concentration of 0.5 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 200W high-pressure mercury lamp for oxidation pretreatment for 24 hours to form a slurry activation solution.

[0061] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then sodium thiosulfate of the copper amine gold leaching agent system with a concentration of 0.08 mol / L was added. The process was carried out in air atmosphere and gold leaching was performed at 25°C and 500 r / min for 24 h with stirring.

[0062] Example 7 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is between 18 μm and 74 μm, accounting for more than 90%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0063] S2. Add hydrogen peroxide to the slurry at a concentration of 0.5 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 1000W high-pressure mercury lamp for oxidation pretreatment for 24 h to form a slurry activation solution.

[0064] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then sodium thiosulfate of the copper amine gold leaching agent system with a concentration of 0.08 mol / L was added. The process was carried out in air atmosphere and gold leaching was performed at 25°C and 500 r / min for 24 h with stirring.

[0065] Example 8 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is between 18 μm and 74 μm, accounting for more than 90%, and then a slurry is prepared and the slurry mass concentration is adjusted to 12%.

[0066] S2. Add hydrogen peroxide to the slurry at a concentration of 0.5 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for oxidation pretreatment for 24 h to form a slurry activation solution.

[0067] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then sodium thiosulfate of the copper amine gold leaching agent system with a concentration of 0.08 mol / L was added. The process was carried out in air atmosphere and gold leaching was performed at 25°C and 500 r / min for 24 h with stirring.

[0068] Example 9 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is between 18 μm and 74 μm, accounting for more than 90%, and then a slurry is prepared and the slurry mass concentration is adjusted to 35%.

[0069] S2. Add hydrogen peroxide to the slurry at a concentration of 0.5 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for oxidation pretreatment for 24 h to form a slurry activation solution.

[0070] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then sodium thiosulfate of the copper amine gold leaching agent system with a concentration of 0.08 mol / L was added. The process was carried out in air atmosphere and gold leaching was performed at 25°C and 500 r / min for 24 h with stirring.

[0071] Example 10 A pretreatment method for high-sulfur arsenic-gold ore leaching rate includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is 18-74 μm or more, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0072] S2. Add potassium persulfate to the slurry at a concentration of 0.5 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for oxidation pretreatment for 24 h to form slurry activation solution.

[0073] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then sodium thiosulfate of the copper amine gold leaching agent system with a concentration of 0.08 mol / L was added. The process was carried out in air atmosphere and gold leaching was performed at 25°C and 500 r / min for 24 h with stirring.

[0074] Example 11 A pretreatment method for high-sulfur arsenic-gold ore leaching rate includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is 18-74 μm or more, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0075] S2. Add hydrogen peroxide to the slurry at a concentration of 0.5 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for 24 hours to form an activating solution for the slurry.

[0076] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then sodium thiosulfate of the copper amine gold leaching agent system with a concentration of 0.08 mol / L was added. The process was carried out in air atmosphere and gold leaching was performed at 25°C and 500 r / min for 24 h with stirring.

[0077] Example 12 A pretreatment method for high-sulfur arsenic-gold ore leaching rate includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is 18-74 μm or more, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0078] S2. Add hydrogen peroxide to the slurry at a concentration of 0.5 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top and sides of the slurry with 600W high-pressure mercury lamps for 24 hours to form an activating solution for the slurry.

[0079] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then sodium thiosulfate of the copper amine gold leaching agent system with a concentration of 0.08 mol / L was added. The process was carried out in air atmosphere and gold leaching was performed at 25°C and 500 r / min for 24 h with stirring.

[0080] Example 13 A pretreatment method for high-sulfur arsenic-gold ore leaching rate includes the following steps: S1, a high-sulfur arsenic gold ore, is a typical high-sulfur arsenic Carlin-type refractory gold ore with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground until the particle size is 18-74 μm or more, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0081] S2. Add hydrogen peroxide to the slurry at a concentration of 0.5 mol / L, stir at 25°C and 450 r / min, and simultaneously irradiate the top of the slurry with a 600W high-pressure mercury lamp for oxidation pretreatment for 24 h to form a slurry activation solution.

[0082] S3. The pH of the slurry activation solution was adjusted to 10.5 using sodium hydroxide, and then sodium cyanide, a gold leaching agent, was added at a concentration of 0.08 mol / L. The leaching was carried out in air atmosphere and the gold was leached at 25°C and 500 r / min for 24 h with stirring.

[0083] Comparative Example 1 A pretreatment method for high-sulfur arsenic-gold ore leaching rate includes the following steps: S1 is a typical high-sulfur arsenic gold ore of the Carlin type, with a gold grade of 32 g / t, a sulfur content of 24%, and an arsenic content of 28%. The high-sulfur arsenic gold ore is ground to a particle size of 18 μm, accounting for 95%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0084] S2. Add hydrogen peroxide to the slurry at a concentration of 0.15 mol / L, and perform oxidation pretreatment at 25°C and 450 r / min for 24 h to form a slurry activation solution.

[0085] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then cicadas were added at a rate of 20 kg / t. The process was carried out in air atmosphere, and the gold leaching treatment was carried out at 25°C and 500 r / min for 24 h with stirring.

[0086] Comparative Example 2 A pretreatment method for high-sulfur arsenic-gold ore leaching rate includes the following steps: S1 is a typical high-sulfur arsenic gold ore of the Carlin type, with a gold grade of 6 g / t, a sulfur content of 13%, and an arsenic content of 15%. The high-sulfur arsenic gold ore is ground to a particle size of 18 μm, accounting for 95%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0087] S2. Add hydrogen peroxide to the slurry at a concentration of 0.15 mol / L, and perform oxidation pretreatment at 25°C and 450 r / min for 24 h to form a slurry activation solution.

[0088] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then cicadas were added at a rate of 20 kg / t. The process was carried out in air atmosphere, and the gold leaching treatment was carried out at 25°C and 500 r / min for 24 h with stirring.

[0089] Comparative Example 3 A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides includes the following steps: S1 is a typical high-sulfur arsenic gold ore of the Carlin type, with a gold grade of 18 g / t, a sulfur content of 20%, and an arsenic content of 22%. The high-sulfur arsenic gold ore is ground to a particle size of 18 μm, accounting for 95%, and then a slurry is prepared and the slurry mass concentration is adjusted to 20%.

[0090] S2. Add hydrogen peroxide to the slurry at a concentration of 0.15 mol / L, and perform oxidation pretreatment at 25°C and 450 r / min for 24 h to form a slurry activation solution.

[0091] S3. The pH of the slurry activation solution was adjusted to 9.8 using sodium hydroxide, and then cicadas were added at a rate of 20 kg / t. The process was carried out in air atmosphere, and the gold leaching treatment was carried out at 25°C and 500 r / min for 24 h with stirring.

[0092] The gold leaching rates of Examples 1 to 13 and Comparative Examples 1 to 3 were tested. The gold leaching rate was determined using atomic absorption spectrophotometry to measure the gold content in the leachate. The specific steps are as follows: Step 1, take an appropriate amount of leachate sample and measure it using a flame atomic absorption spectrophotometer; Step 2, use standard gold solutions such as 0.5 mg / L, 1.0 mg / L, 2.0 mg / L, 5.0 mg / L, and 10.0 mg / L, and plot a standard curve based on the measured values ​​of the absorption spectrophotometer and calibrate the sample; Step 3, calculate the gold leaching rate based on the total gold content in the original ore sample and the gold content measured in the leachate: Gold leaching rate (%) = (Gold content in leachate / Gold content in original ore) × 100%. The test was repeated three times, and the average value was taken to ensure data accuracy. The results are shown in Table 1.

[0093] Table 1. Gold leaching rates of the examples and comparative examples As shown in Table 1, the significant effect of the synergistic effect of UV photocatalysis and peroxide on the leaching rate of high-sulfur arsenic gold ore can be clearly observed. Examples 1 to 9, using different conditions for synergistic pretreatment with UV photocatalysis and peroxide, all achieved high gold leaching rates, ranging from 78.96% to 93.45%. In contrast, Comparative Examples 1 to 3, which only used peroxide treatment, showed significantly lower gold leaching rates, only 56.71% to 71.52%, fully demonstrating the crucial role of UV photocatalysis.

[0094] When the concentration of the oxidant was changed, the gold leaching rates were 82.15%, 87.64%, and 91.87% for hydrogen peroxide concentrations of 0.1 mol / L in Example 4, 0.5 mol / L in Example 1, and 1.0 mol / L in Example 5, respectively. This shows that increasing the concentration of hydrogen peroxide can significantly improve the gold leaching rate. This is because more active free radicals are generated at higher concentrations, which enhances the oxidation ability against sulfides and arsenides.

[0095] When the UV light power was changed, such as 200W in Example 6, 600W in Example 1, and 1000W in Example 7, the gold leaching rates were 78.96%, 87.64%, and 93.45%, respectively. This indicates that high-power UV irradiation can more effectively promote the decomposition of peroxides to generate free radicals and accelerate mineral oxidation. In particular, when the power is increased to 1000W, the gold leaching rate is significantly improved.

[0096] When the mass concentration of the slurry was changed, such as 12% for Example 8, 20% for Example 1, and 35% for Example 9, the gold leaching rates were 85.38%, 87.64%, and 84.27%, respectively. This indicates that the slurry concentration has little effect on the leaching rate. However, the gold leaching rate was best when the mass concentration of the slurry in Example 1 was 20%, which ensured sufficient reactant concentration while avoiding the mass transfer limitation caused by high concentration.

[0097] When the type of oxidant was changed, such as potassium persulfate in Example 10 and hydrogen peroxide in Example 11, the gold leaching rates were 86.23% and 83.91%, respectively, which are similar to 87.64% for hydrogen peroxide in Example 1. This indicates that all types of peroxides can achieve efficient leaching under ultraviolet photocatalysis, but sodium peroxide is slightly better.

[0098] When the range of ultraviolet irradiation was changed, such as with dual ultraviolet irradiation in Example 12, the gold leaching rate reached 94.12%, indicating that increasing the light intensity and coverage area can further improve the leaching efficiency, but the equipment cost and energy consumption also increase accordingly. When the gold leaching agent was changed, such as with sodium cyanide in Example 13, the gold leaching rate was 91.56%, slightly higher than in Example 1, showing that different gold leaching agents can also affect the final leaching effect.

[0099] In summary, the pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides provided by this invention, especially the key role of the synergistic effect of ultraviolet photocatalysis and peroxides, allows for a gold leaching rate increase of approximately 30% or more under optimal conditions (high-power ultraviolet light + appropriate concentration of peroxides). This method achieves efficient leaching under mild conditions, avoiding the high energy consumption and environmental pollution problems of traditional high-temperature roasting or high-pressure oxidation methods, and has significant industrial application value.

[0100] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

[0101] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxide treatment, characterized in that, Includes the following steps: The high-sulfur arsenic gold ore was ground and then formulated into a slurry. An oxidant is added to the slurry, and the high-sulfur arsenic gold ore is pretreated by oxidation under ultraviolet light catalysis to form a slurry activation solution. Adjust the pH of the slurry activation solution to 9-12, add gold leaching agent to the slurry complexing solution, and perform stirring and gold leaching treatment.

2. The pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides according to claim 1, characterized in that, The ultraviolet photocatalysis method uses a high-pressure mercury lamp with a power of 100W to 1000W.

3. The pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides according to claim 1, characterized in that, The concentration of oxidant in the slurry is 0.0001 mol / L to 3 mol / L.

4. The pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides according to claim 1, characterized in that, The oxidant is at least one of hydrogen peroxide or persulfate.

5. The pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides according to claim 1, characterized in that, The oxidation pretreatment temperature is 10℃~90℃, the time is 12h~24h, and the stirring rate is 80r / min~500r / min.

6. In the pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides according to claim 1, the concentration of gold leaching agent in the slurry activation solution is 0.01 mol / L to 1 mol / L.

7. The pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides according to claim 1, characterized in that, The gold leaching agent is at least one of the following: sodium thiosulfate (copper amine system), cyanide-containing leaching agent, thiourea, chloride, cicada, or green gold.

8. The pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides according to claim 1, characterized in that, The immersion gold treatment was carried out in an air atmosphere, with an immersion temperature of 10℃~90℃, an immersion time of 4h~24h, and a stirring rate controlled at 80r / min~500r / min.

9. The pretreatment method for enhancing the leaching rate of high-sulfur arsenic gold ore by strengthening peroxides according to claim 1, characterized in that, After grinding, more than 90% of the high-sulfur arsenic gold ore particles are between 18μm and 74μm in size, and the mass concentration of the slurry is between 10% and 40%.

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